jsp使用filter登录状态验证 – 小飞侠

jsp使用filter登录状态验证

Post author:xfxia
Post published:2023年9月21日
Post category:其他

一，编写jsp登录页面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<!--登录界面  -->
<form action="logonServlet.do" method="post">
	<div>
		账户名:<input type='text' name="oname"/>
	</div>
	<div>
		密码:<input type="password" name="opwd"/>
	</div>
	<button>登录</button>
	<!--引入版权  -->
	<%@ include file="c.jsp" %>
</form>
</body>
</html>

二，编写后端servlet登录程序

package com.jmh.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.SQLException;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.jmh.dao.Tb_LogonDao;
import com.jmh.entity.Tb_Logon;

/**
 * 登录
 *
 */
public class LogonServlet extends HttpServlet{
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	this.doGet(req, resp);
	}
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	//设置编码
/*		req.setCharacterEncoding("utf-8");
		resp.setContentType("text/html;charset=utf-8");*/
	//获取out、session对象
		PrintWriter out = resp.getWriter();
		HttpSession session = req.getSession();
	//处理业务逻辑代码
		//获取传入过来的值
		String oname = req.getParameter("oname");
		String opwd = req.getParameter("opwd");
		//实例化实体类
		Tb_Logon lo=new Tb_Logon(oname, opwd);
		//实例化方法类
		Tb_LogonDao tbl=new Tb_LogonDao();
		try {
			boolean logon = tbl.Logon(lo);
			if(logon) {//登录成功
				//使用session
				//登录状态:登录成功后把用户名传入给session作用域
				session.setAttribute("oname", oname);
				req.getRequestDispatcher("跳转登录成功后的页面").forward(req, resp);
			}else {//登录失败
				out.print("<script>alert('登录失败!');location.href='跳转登录页面'</script>");
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

}

三，配置servlet程序web.xml

哈哈哈上编使用session和cookie做登录状态判断小辉没有配置哈哈希望大家都能自己配置哦

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>jsp-04</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <!--登录  -->
  <servlet>
  	<servlet-name>建议填写该配置的类名</servlet-name>
  	<servlet-class>筛选完整路径(包名+类名)</servlet-class>
  </servlet>
  <servlet-mapping>
  	<servlet-name>建议填写该配置的类名</servlet-name>
  	<url-pattern>/建议填写该配置的类名.do(=可以通过类名+.do来访问页面)</url-pattern>
  </servlet-mapping>
</web-app>

四，编写筛选filter登录状态判断

小编也同时利用了filter筛选做了编码设置

package com.jmh.filter;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * 筛选
 *
 */
public class SetEcodingLogon implements Filter{

	@Override
	public void destroy() {
		//筛选被摧毁
	}

	@Override
	public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
			throws IOException, ServletException {
		//筛选器被执行/处理
		//设置编码
		HttpServletRequest req=(HttpServletRequest)arg0;
		HttpServletResponse resp=(HttpServletResponse)arg1;
		req.setCharacterEncoding("utf-8");
		resp.setContentType("text/html;charset=utf-8");
		//获取out对象
		PrintWriter out = resp.getWriter();
		//获取session对象
		HttpSession session = req.getSession();
		//获取请求地址
		String uri = req.getRequestURI();
		if(uri.indexOf("logon.jsp")>-1||uri.indexOf("logonServlet.do")>-1) {
			//如果是登录页面或者登录servlet就放行
			arg2.doFilter(arg0, arg1);
			return;
		}
		//获取session里面的值
		String s = (String)session.getAttribute("oname");
		//如果跳转指定页面判断session里面没有值的话就跳转登录界面
		if(null == s) {
			//使用js方式跳转页面登录页面
			out.print("<script>alert('请先登录');location.href='跳转登录页面';</script>");
		}
		//放行
		arg2.doFilter(arg0, arg1);
	}

	@Override
	public void init(FilterConfig arg0) throws ServletException {
		//筛选被创建
	}

}

五，配置filter筛选web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>jsp-04</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <!-- 配置筛选 -->
  <filter>
  	<filter-name>建议填写该配置的类名</filter-name>
  	<filter-class>筛选完整路径(包名+类名)</filter-class>
  </filter>
  <filter-mapping>
  	<filter-name>建议填写该配置的类名</filter-name>
  	<url-pattern>/*(/*=输入什么都可以执行筛选)</url-pattern>
  </filter-mapping>
</web-app>

版权声明：本文为m0_63300795原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。

原文链接：https://blog.csdn.net/m0_63300795/article/details/124693836